Philadelphus mearnsii
in N. L. Britton et al., N. Amer. Fl. 22: 174. 1905.
Shrubs, 5–15(–40) dm. Stems tan-brown, weathering gray, striate, stiffly divaricately branched, strigose-sericeous; internodes 0.1–3.5 cm; short shoots often present; axillary buds exposed. Leaves: petiole 0.5–4 mm; blade green or gray-green abaxially and adaxially, oblong-lanceolate, linear-lanceolate, or elliptic to ovate, 0.5–1.7(–3) × 0.1–0.6(–1.1) cm, coriaceous, margins entire, ± revolute, surfaces ± equally moderately strigose, hairs appressed, coarse, 0.2–0.6(–0.9) mm, without understory of coiled-crisped hairs; veins inconspicuous. Inflorescences: flowers solitary, produced from previous year's long shoots, often appearing axillary. Pedicels 0.5–2 mm. Flowers: hypanthium sparsely to moderately strigose-sericeous or glabrous; sepals ovate-lanceolate, 2–3.5(–4.2) × 1.3–2.3 mm, apex acute to acuminate-caudate, abaxial surface sparsely to moderately strigose-sericeous or glabrous, adaxial surface glabrous except villous along distal margins; petals white, oblong-lanceolate to broadly oblong-ovate, (5–)7–8.5(–10) × 2.5–4.5(–5.8) mm; stamens 13–18(–24); filaments distinct, 1.3–4 mm; style 1, clavate, 2–3.2 mm, narrow base 0.5–1.5 mm; stigmatic portion 1.3–2 mm, distally lobed to 0.5 mm. Capsules ovoid-turbinate, 3–5.5 × 3.2–5.5 mm, sepals ± persistent at distal 1/3 or more distally, capsule distal surface impressed in 4(–8) radial lines. Seeds not caudate, 1–1.2 mm.
Phenology: Flowering Apr–Jun; fruiting May–Nov.
Habitat: Limestone mountains, oak-pinyon zones.
Elevation: 1300–1800(–2200) m.
Distribution
N.Mex., Tex., Mexico (Coahuila).
Discussion
Philadelphus hitchcockianus, with its hypanthium and abaxial sepal surfaces glabrous, is here synonymized with P. mearnsii, which has its hypanthium and abaxial sepal surfaces moderately sericeous-strigose; substantial variation in this character is found in several populations. Hu S. Y. (1954–1956) alleged that P. hitchcockianus and P. mearnsii also differ in fruit size; however, that character is variable and overlapping.
Selected References
None.